The mechanism by which a bacteriophage packages DNA into its capsid, an essential step in its replicative cycle, is poorly understood. Several models exist for the mechanical action of the molecular motor responsible for the translocation of the DNA into the viral head, none of which have been verified experimentally. Techniques such as optical tweezers, atomic force microscopy, and fluorescence microscopy are sensitive enough to probe molecular machines at the single-molecule level. The packaging motor of the bacteriophage phi29 packaging motor, this study will address the more general question of how mature converts chemical energy into mechanical action. Moreover, since the models developed for one type of phage are likely to be universally applicable to other related viruses, this investigation may lead to targets against which to develop new anti-viral drugs.